It's not just the use of steroids that gets an examination in this Law And Order story. It's the notion that Reynaldo Rosales would rather be known as a cheat than as gay.
Personally though at the point in time this episode was made I think that Rosales if he was fighting for his life might feel that blackmail about that would be a defense a jury could nullify over. But that he was cheating because of steroid abuse might be another matter. The truth might shatter some illusions, the lie would definitely put his career in jeopardy. Look what it did to Alex Rodriguez and Barry Bonds.
The victim was a chauffeur for a limousine service that Rosales used on occasion and he was blackmailing Rosales over being in the closet. The District Attorney learns about that quite accidentally when defense attorney Jay Sanders accidentally includes it with a motion he's serving. He protests and the judge excludes evidence of Rosales sexual orientation. Imagine gaining an advantage through your own incompetence, turn that one over in your mind. I couldn't buy that ruling at all.
I think baseball is poised to have openly gay players myself so seen now the story is a quaint one.